All plastic shotshell case with transversely oriented undulations on outer cylindrical surface

ABSTRACT

An all plastic shotshell case molded with the transverse base wall and cylindrical sidewall integral of and in one piece with each other, and the outer surface of the cylindrical sidewall having undulations all along the length thereof and oriented transversely of the longitudinal orientation of the cylindrical sidewall, said transverse undulations forming rings extending circumferentially around the cylindrical sidewall, or said undulations being in the pattern of circles, dots, squares, knurls or other shapes.

i] ite tates Herter atent H 1 [451 May 7,1974

[ ALL PLASTIC SHOTSHELL CASE WITH TRANSVERSELY ORIENTED UNDULATIONS ONOUTER CYLINDRHCAL SURFACE [75] Inventor:

[73] Assignee: Herters Inc., Waseca, Minn.

[22] Filed: Nov. 8, 1971 [21] Appl. No.: 196,627

George L. Herter, Waseca, Minn.

[52] US. Cl. 102/43 P [51] Int. Cl. F42b 7/06 [58] Field of Search102/42 R, 43 R, 43 P [56] References Cited UNITED STATES PATENTS 185,54812/1876 Kinney 102/43 R 3,363,562 1/1968 Stadler et al. 102/43 P FOREIGNPATENTS OR APPLICATIONS 1,448,965 8/1966 France 102/43 P 1,114,1345/1968 Great Britain 102/43 P Primary Examiner-Stephen C. BentleyAttorney, Agent, or FirmWilliamson, Bains & Moore [5 7] ABSTRACT An allplastic shotshell case molded with the transverse base wall andcylindrical sidewall integral of and in one piece with each other, andthe outer surface of the cylindrical sidewall having undulations allalong the length thereof and oriented transversely of the longitudinalorientation of the cylindrical sidewall, said transverse undulationsforming rings extending circumferentially around the cylindricalsidewall, or said undulations being in the pattern of circles, dots,vsquares, knurls or other shapes.

3 Claims, 5 Drawing Figures PATENTEBIAY 7:914

Q INVENTOR BY g'eor ye L.Herter 90%4 yam ATTOE/VEV ALL PLASTIC SHOTSHELLCASE WITH TRANSVERSELY ORIENTED UNDULATIONS ON OUTER CYLINDRICAL SURFACEBRIEF SUMMARY OF THE INVENTION It has been found that all plasticshotshell cases wherein the transverse base wall and the cylindricalsidewall are integral of and in one piece with each other and are moldedof any of a number of types of plastic such as linear polyethylene, willhave more strength where the outer surface of the cylindrical sidewallis provided with a plurality of shallow undulations throughout theentire length of the cylindrical sidewall. Such undulations may bearranged in any of a number of patterns on the outer surface of thesidewall, and it has been found advantageous to arrange such undulationsso that rings are formed extending circumferentially around the entireperiphery of the cylindrical sidewalls, and all along the length of thesidewall case. The result is to strengthen the walls of the case, andthis is caused, at least in part, because during the filling of the moldin which the shotshell case is formed, the plastic is flowed into themold cavity in a direction longitudinally of the cylindrical sidewallbeing formed, and therefore across the undulations in the mold partforming the outer surface of the cylindrical sidewall. The moltenplastic, during filling of the mold cavity, flows across theseundulations in the mold part and causes some degree of laminating of theplastic during the flow which results in the increased strength of theplastic after the plastic is allowed to cure and harden.

It has been found that the undulations, oriented transversely of thelongitudinal orientation of the cylindrical sidewall may be arranged invarious patterns such as the rings extending circumferentially of thecylindrical sidewall, but the pattern may take the form of circles,dots, squares, knurls or any other convenient shape which nests togetherinto an overlapping relation and which have at least a portion thereofextending transversely of the longitudinal orientation of thecylindrical sidewall.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an enlarged elevation view,partly broken away, and in section, and illustrating a shotshell caseaccording to the present invention, and illustrating the open mouth ofthe case closed with the usual star crimp.

FIG. 2 is a greatly enlarged longitudinal section view takenapproximately at 22 in FIG. 1.

FIG. 3 is a fragmented detail view showing a small portion of the moldparts used in molding the all plastic shotshell case illustrated inFIGS. 1 and 2 to carry out the invention.

FIG. 4 is a greatly enlarged detail elevation view of the outer surfaceof a cylindrical shotshell sidewall, and illustrating a modified form ofthe invention.

FIG. 5 is a view similar to FIG. 4 and illustrating a second modifiedform of the invention.

DETAILED DESCRIPTION OF THE INVENTION The all plastic shotshell case isindicated in general by numeral and includes a transversely orientedbase wall 11 and an elongate, substantially cylindrical sidewall 12. Thebase wall 11 and the sidewall 12 are molded integrally of and in onepiece with respect to each other, and are formed of any of a number ofplastics suitable for molding all plastic shotshell cases, such aslinear polyethylene, or an extrusion grade polyethylene material whichis somewhat stiffer in consistency when injected into the mold cavitythan other polyethylenes. The base wall of the shotshell case has anopening 13 therein to receive the primer of the shotshell, and theshotshell case has an open interior 14 for receiving the usual powdercharge, wadding, and shot charge which, when added to the case andprimer, make up the loaded shotshell. In the drawings, the integralclosure 15 is shown in the position of a star crimp for illustrationpurposes, even though no powder or shot charge is contained in theshotshell.

The substantially cylindrical sidewall 12 is provided with a series ofundulations 16a and 16b which are actuall-y grooves and ribs or ridgesrespectively, extending circumferentially around the entire periphery ofthe substantially cylindrical wall 12. It is pointed out that theundulations 16a and 16b are provided on the outer surface of thesidewall, throughout substantially the entire length of the sidewall,and substantially strengthen the case sidewall.

It will be noted that the spacing between undulations may be varied atvarious locations along the length of the case sidewall, and in thisform illustrated, the undulations 16a and 16b are smaller than thespacings between undulations along other portions of the case sidewall.The ribs and grooves formed by the undulations 16a and 16b form a moreefficient sealing relationship with the chamber of the shotgun barrelwhen the case is fired, due to the extreme magnitude of gas pressurethat builds up at the inner chamber 14 of the shotshell case upon firingof the shotshell and deformation of the plastic against the barrel wallat the ribforming undulations 16b.

FIG. 3 illustrates the molding of the shotshell case sidewall and showsa fragmented portion of the mold assembly which includes the mold part20 which cooperates with the core 21 to define the mold cavity 22therebetween. The mold cavity is correspondingly substantiallycylindrically shaped to conform to the shape of the substantiallycylindrical sidewall 12, and of course, the mold cavity 22 also extendsacross the end of the core to shape the plastic which forms the basewall 1 1 of the shotshell case. The mold part 20 has undulations 20a and20b in its surface which form the outer surface of the substantiallycylindrical sidewall 12. As illustrated, the molten plastic 23 isflowed. in a direction longitudinally along the core 21 andlongitudinally of the substantially cylindrical mold cavity 22, asindicated by the direction of arrow A. Because of this flow of theplastic material, the transversely oriented undulations 20a and 20b areencountered as the plastic flows in the direction of arrow A and becauseof the drag or restriction to flow at the undulations 20a,

20b, there is laminating of the plastic during the flow I and aresultant strengthening of the case sidewall after the case is allowedto cure and harden. Of course, because of the undulations, the plastic,as it flows, has a shear location 23.1 as indicated by the dotted linesin FIG. 3, outwardly of which the plastic is retarded in movement andinwardly of which the plastic flows with full velocity in the directionof arrow A.

The resulting all plastic shotshell case 10 has an increased strength inthe substantially cylindrical sidewall 12- due to the presence of theundulations and rings around the periphery thereof.

In the form illustrated in FIG. 4, the outer surface of the sidewall12.] is provided with a plurality of undulations l2.la and l2.lb formingpatterns on the outer surface of the sidewall in the form of a pluralityof clustered circular annuli having a height similar to that of theundulations 16a and 16b illustrated in FIG. 1 wherein these undulationshave a magnitude in a direction transversely of the case sidewall whichis considerably less than the thickness of the sidewall. It will benoted that the circular annuli formed by the undulations 12.10 and l2.lbhave portions oriented transversely of the elongate substantiallycylindrical sidewall case 12.1

In FIG. another form of the invention is illustrated wherein thesubstantially cylindrical sidewall 12.2 is provided with a plurality ofundulations 12.2a and 12.2b arranged in a pattern forming closely nestedsquares or rectangles. It will be noted that portions of the undulations12.2a and 12.2b are oriented transversely of the longitudinalorientation of the substantially cylindrical sidewall.

It should be understood that the undulations on the outer surface of thesidewall may be arranged in other patterns including dots, diamonds,knurls, or any of the other common geometric shapes, which have aportion oriented transversely or at least obliquely transversely of thelongitudinal orientation of the sidewall case.

It will be seen that l have provided a new and improved all plasticshotshell case wherein the outer surface of the substantiallycylindrical sidewall is provided with undulations arranged in a patternwith portions extending transversely of the elongate longitudinalorientation of the substantially cylindrical sidewall effecting astrengthening of the sidewall against outward expansion and rupture dueto pressure developed within the case.

What is claimed is:

1. An all plastic shotshell case comprising:

a substantially cylindrical sidewall of molded plastic open at one end;

a base wall of molded plastic extending transversely of said sidewall atthe opposite end thereof, said sidewall and base wall being formedintegrally as one piece, and said base wall having an opening therein toreceive the primer of the shotshell; and

a plurality of undulations on the outer surface of said sidewallprojecting outwardly therefrom, said undulations being formed integrallywith said sidewall and extending in longitudinally spaced circularpatterns over more than one half of the length of said sidewall up toand along said open end thereof, and said undulations being in the formof circumferentially extending rings of varying width in a directionalong the length of said cylindrical sidewall, with the narrower ringsbeing disposed adjacent said open end of said sidewall and beingdeformable against a shotgun barrel under the pressure developed withinsaid shotshell case upon firing.

2. An all plastic shotshell as defined in claim 1 wherein:

said undulations comprise a plurality of closely clustered annuli ofcircular shape.

3. An all plastic shotshell comprising:

a substantially cylindrical sidewall of molded plastic open at one end;

a base wall of molded plastic extending transversely of said sidewall atthe opposite end thereof, said sidewall and base wall being formedintegrally as one piece, and said base wall having an opening therein toreceive the primer of the shotshell; and

open end of said sidewall.

1. An all plastic shotshell case comprising: a substantially cylindricalsidewall of molded plastic open at one end; a base wall of moldedplastic extending transversely of said sidewall at the opposite endthereof, said sidewall and base wall being formed integrally as onepiece, and said base wall having an opening therein to receive theprimer of the shotshell; and a plurality of undulations on the outersurface of said sidewall projecting outwardly therefrom, saidundulations being formed integrally with said sidewall and extending inlongitudinally spaced circular patterns over more than one half of thelength of said sidewall up to and along said open end thereof, and saidundulations being in the form of circumferentially extending rings ofvarying width in a direction along the length of said cylindricalsidewall, with the narrower rings being disposed adjacent said open endof said sidewall and being deformable against a shotgun barrel under thepressure developed within said shotshell case upon firing.
 2. An allplastic shotshell as defined in claim 1 wherein: said undulationscomprise a plurality of closely clustered annuli of circular shape. 3.An all plastic shotshell comprising: a substantially cylindricalsidewall of molded plastic open at one end; a base wall of moldedplastic extending transversely of said sidewall at the opposite endthereof, said sidewall and base wall being formed integrally as onepiece, and said base wall having an opening therein to receive theprimer of the shotshell; and a plurality of undulations on the outersurface of said sidewall projecting outwardly therefrom, saidundulations extending transversely with respect to said cylindricalsidewall in generally circular patterns over a substantial portion ofthe length of said sidewall up to and along said open end thereof, andsaid undulations being of varying width in a direction along the lengthof said sidewall with the narrowest undulations being disposed adjacentsaid open end of said sidewall.